add support for ARM64 architecture

.github/workflows/publish.yml

@@ -19,6 +19,8 @@ jobs:
 
     - name: Set up Docker Buildx
       uses: docker/setup-buildx-action@v2
+      with:
+        platforms: linux/amd64,linux/arm64
 
     - name: Integration tests
       run: "docker compose \
@@ -41,6 +43,7 @@ jobs:
         build-args: |
           KOMPANION_VERSION=${{ steps.get_tag.outputs.TAG }}
         push: true
+        platforms: linux/amd64,linux/arm64
         tags: |
           vanadium23/kompanion:latest
           vanadium23/kompanion:${{ steps.get_tag.outputs.TAG }}

Dockerfile

@@ -1,29 +1,60 @@
+# Dockerfile (Minimal Changes)
+
+# Define target architecture as a build argument.
+# BuildKit automatically sets this when using --platform.
+ARG TARGETARCH
+
 # Step 1: Modules caching
+# Use a multi-arch Go base image. BuildKit will select the correct one based on TARGETARCH.
 FROM golang:1.22.5-alpine as modules
+
+# Set GOOS and GOARCH based on the build argument for this stage.
+# This ensures go mod download caches for the correct target architecture.
+ENV GOOS=linux GOARCH=${TARGETARCH}
+
 COPY go.mod go.sum /modules/
 WORKDIR /modules
 RUN go mod download
 
 # Step 2: Builder
+# Use a multi-arch Go base image for the builder stage.
 FROM golang:1.22.5-alpine as builder
-RUN apk add --update gcc musl-dev
+RUN apk add --update gcc musl-dev # Keep update for minimal change
+
+# Set GOOS and GOARCH for the builder environment.
+# This will be used by the go build command.
+ENV GOOS=linux GOARCH=${TARGETARCH}
+
+# Copy modules cache built for the *same* target architecture
 COPY --from=modules /go/pkg /go/pkg
+
 COPY . /app
 WORKDIR /app
 
+# Define KOMPANION_VERSION as a build argument
 ARG KOMPANION_VERSION=local
 ENV KOMPANION_VERSION=$KOMPANION_VERSION
 
-RUN GOOS=linux GOARCH=amd64 \
-    go build -ldflags "-X main.Version=$KOMPANION_VERSION" -tags migrate -o /bin/app ./cmd/app
+# Build the application. Use the GOOS/GOARCH from the environment.
+# REMOVE the hardcoded GOOS=linux GOARCH=amd64.
+RUN go build -ldflags "-X main.Version=$KOMPANION_VERSION" -tags migrate -o /bin/app ./cmd/app
 
 # Step 3: Final
+# Keep the same base image as the original for minimal change.
+# This image is multi-arch, and BuildKit will select the correct variant.
 FROM golang:1.22.5-alpine
-ENV GIN_MODE=release
 
+ENV GIN_MODE=release
 WORKDIR /
+
+# Copy web assets from the builder stage
 COPY --from=builder /app/web /web
+
+# Copy the architecture-specific binary from the builder stage
 COPY --from=builder /bin/app /app
+
+# Copy CA certs as in the original
 COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
 
-CMD ["/app"]
+# Set the command to run the application
+CMD ["/app"]